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Usage Examples of "Neural Circuit" and Related Terms
Topic This article lists and discusses examples of how the term "neural circuit" and related terms are used, both in the popular press and also in neuroscience and other scientific publications. Related terms include, e.g., "neural circuitry", "neuronal circuit", "brain circuit", "circuitry in the brain", "brain wiring", "neuronal path", "neural pathway", etc. For greater completeness, this article also lists examples of neuroscience publications that avoid using the term "neural circuit". Caveat: This article is by no means an exhaustive list of all usage examples of "neural circuit" and related terms--many others could be found and listed. Popular Press Items Using the Term "Neural Circuit" or Related Terms (in chronological order) Macknik et al., 2012 Macknik, S.L., and Martinez-Conde, S., "Mind-warping Visions: 10 Brain Twisters Compete to be the Best Illusion of 2011", Scientific American Mind, January/February 2012, pp. 46-51: *Page 47: "Illusions also offer a window into how our neural circuits create our first-person experience of the world." Grady, D., "How to Teach An Old Brain New Tricks", The New York Times, March 8, 2012, pp. F1, F6: *Page F1: Quoting Arthur Toga, a professor of neurology and director of the laboratory of neuroimaging at the University of California, Los Angeles about what happens when two people have a conversation: "You're changing the circuitry in your brain. That is because you have changed something in your brain to retain that memory." Castro, J., "Sleep's Secret Repairs", Scientific American Mind, May/June 2012, pp. 42-45, discusses a provocative new theory about the purpose of sleep, proposed by neuroscientist Giulio Tononi, University of Wisconsin-Madison: *At pages 42 and 44, Castro describes how Tononi surmised that the "neural circuits" buttressing recently formed memories can be fortified a certain number of times, but then they reach their maximum strength. *At page 44, we learn that electric current flowing through synapses creates the slow-wave signal recorded with electrodes on the scalp. *At page 45, we further learn about neurons constantly chattering with one another through small electric currents shuttling through synapses--the more current flowing, the stronger the synapse. Also, the caption of a figure on page 45 clarifies that an axon is a neuron's main conduit for incoming information. *Caveat: The second and third items above illustrate how far some go in thinking of neurons as being connected in circuits. These views might, however, be inaccurate: Present-day theory generally holds that neurotransmitter, not electric current, flows across the cleft of a synapse, and that a neuron receives incoming information through synapses on its dendrites and soma, not through its axon. Koch, C., "Searching for the Memory", Scientific American Mind, July/August 2012, pp. 22-23, argues that percepts and memories arise in networks of neurons connected by synapses, and describes experiments in which triggering certain neurons in a mouse's hippocampus' dentate gyrus, i.e. neurons that had been activated in a dangerous environment B, can cause a freezing reaction even in a non-dangerous, neutral environment A. *At page 23, Koch summarizes: "Neural circuits in the dentate gyrus of the hippocampus wired up to express an aversive event that happened at B are sufficient to evoke the associated aversive memory, even though the subjects never had experienced anything bad in A." Looking forward, Koch points out: "Whether these circuits are also necessary for this memory, that is, whether deleting these neurons will remove the memory--shades of Eternal Sunshine of the Spotless Mind--remains to be determined (soon)." Neuroscience Publications Using the Term "Neural Circuit" or Related Terms (in alphabetical order by first author's last name) Anderson, M.L., "Neural reuse: A fundamental organizational principle of the brain", Behavioral and Brain Sciences, Vol. 33, Issue 4, August 2010, pp. 245-313: *Page 245 describes reuse of neural circuitry for various cognitive purposes to be a central organizational principle, and also mentions that circuits can continue to acquire new uses after an initial or original function is established. *Page 246 suggests that "low-level neural circuits are used and reused for various purposes in different cognitive and task domains". Byrne, J.H., and Roberts, J.L., Eds., From Molecules to Networks: An Introduction to Cellular and Molecular Neuroscience, 2d Ed., Burlington, Mass.: Elsevier/Academic Press, 2009: *Hof, P.R., Nimchinsky, E.A., Kidd, G., Claudio, L., and Trapp, B.D., "Cellular Components of Nervous Tissue", Chapter 1, pp. 1-17, at page 1, explain that neurons form circuits constituting the structural basis for brain function, and distinguish macrocircuits that project between brain regions from microcircuits with local cell-cell interactions in a region. *Byrne, J.H., and Shepherd, G.M., "Complex Information Processing in Dendrites", Chapter 17, pp. 489-511, offers an approach that relates electrical current in dendrites to information processing in neural circuits; for example, page 489 defines "microcircuits" as "a specific pattern of interactions performing a specific functional operation; page 490 proposes that dendrites do whatever is required to process information within their neuron or neuronal circuit. *Knierim, J.J., "Information Processing in Neural Networks", Chapter 18, pp. 513-537, begins at page 513 by arguing that understanding how neural circuits support brain and nervous system functions is a primary goal of systems, behavioral, and cognitive neuroscience. At page 515, Fig. 18.2 illustrates a simple neural circuit, the stretch reflex. At pages 524-527, a section headed "Iconic Neural Circuits" describes and illustrates a variety of neural circuits that are building blocks of complex neural networks. Page 527 discusses the plasticity of neural circuits. At pages 528-535, a section headed "Example Circuits" describes and illustrates a number of real neural circuits, ranging from relatively simple to complex. *Byrne, J.H., LaBar, K.S., LeDoux, J.E., Schafe, G.E., Sweatt, J.D., and Thompson, R.F., "Learning and Memory: Basic Mechanisms", Chapter 19, pp. 539-608, describe several specific neural circuits: Pages 561-575 describe neural circuits in Aplysia and other invertebrates; pages 575-595 relate to vertebrates. Jacobs, G.H., Williams, G.A., Cahill, H., and Nathans, J., "Emergence of Novel Color Vision in Mice Engineered to Express a Human Cone Photopigment", Science, Vol. 315, No. 5819, March 2007, pp. 1723-1725: *Page 1723 argues that color vision requires both multiple photopigments and appropriate neural wiring. *Page 1725 proposes that neural circuitry emerged for comparing new and existing sensory responses. Purves, D., Augustine, G.J., Fitzpatrick, D., Hall, W.C., LaMantia, A.-S., McNamara, J.O., and White, L.E., Eds., Neuroscience, Fourth Edition, Sunderland, Mass.: Sinauer Associates, 2008: *At pages 11-13, a section headed "Neural Circuits" explains that, rather than functioning in isolation, neurons in ensembles process information, providing the basis of sensation, perception, and behavior. *Chapter 23, "Construction of Neural Circuits", pages 577-609, describes roles of cytoskeleton in constructing neural circuits, including axon growth cone motility and synapse formation. Purves, D., Augustine, G.J., Fitzpatrick, D., Hall, W.C., LaMantia, A.-S., and White, L.E., Eds., Neuroscience, Fifth Edition, Sunderland, Mass.: Sinauer Associates, 2012 is very similar to the Fourth Edition, and includes one chapter title changed to include "Neural Circuits": *Chapter 24, "Modification of Neural Circuits as a Result of Experience, pages 537-557. Neuroscience Publications That Avoid the Term "Neural Circuit" (in alphabetical order by first author's last name) Sanes, D.H., Reh, T.A., and Harris, W.A., Development of the Nervous System, 3rd Ed., Burlington, Mass.: Elsevier/Academic Press, 2012; this book resembles Squire, above, but is less comprehensive, and very rarely uses terms like "neural circuit". One exception has been found: *Pages 290-291, in a section titled "More Complex Behavior is Assembled from the Integration of Simple Circuits", begins by discussing certain circuits such as in embryonic leechesBloom, and then describes Coghill's investigating how neural circuits develop to generate behavior. Squire, L.R., Berg, D., Bloom, F.E., du Lac, S., Ghosh, A., and Spitzer, N.C., Eds., Fundamental Neuroscience, Third Edition, Burlington, Mass.: Academic/Elsevier, 2008; several chapters of this comprehensive neuroscience textbook use terms like "path" and "pathway", but terms like "neural circuit" appear rarely. A few examples have been found: *Bloom, F.E., "Fundamentals of Neuroscience", pp. 3-13, describes basic patterns of "neuronal circuitry" at pages 6-7. *Cline, H., Ghosh, A., and Jan, Y.-N., "Dendritic Development", pp. 491-516, mentioning developing neuronal circuits at page 491 and the function of neuronal circuits at page 510. *Knudsen, E.I., "Early Experience and Sensitive Periods", pp. 517-532, describes development of neural circuits at page 517, and introduces four examples of circuits that have been relatively well studied, specifically "the circuits involved in (1) song learning in songbirds, (2) sound localization in owls, (3) binocular representation in the visual cortex, and (4) temperament in rats." *Floeter, M.K. and Mentis, G.Z., "The Spinal and Peripheral Motor System", pp. 677-697, describe central pattern generating circuits at page 679, descending control of spinal circuits at page 693, and plasticity in spinal cord circuits at page 696. Other Scientific Publications (in alphabetical order by first author's last name, then in chronological order within a first author) Mancuso, K., Hauswirth, W.W., Li, Q., Connor, T.B., Kuchenbecker, J.A., Mauck, M.C., Neitz, J., and Neitz, M., "Gene therapy for red-green colour blindness in adult primates", Nature, Vol. 461, 8 October 2009, pp. 784-787: *The abstract, on page 784, explains how adding a third type of cone pigment to dichromatic retinas provided the receptoral basis for trichromatic colour vision, allowing exploration of "the requirements for establishing the neural circuits for a new dimension of colour sensation." *Page 786 proposes that a new dimension of colour vision exploited pre-existing blue-yellow circuitry Mancuso, K., Mauck, M.C., Kuchenbecker, J.A., Neitz, M., and Neitz, J., "Chapter 72: A Multi-State Color Model Revisited: Implications for a Gene Therapy Cure for Red-Green Colorblindness", in Anderson, R.E., LaVail, M.M., and Hollyfield, J.G., Eds., Retinal Degenerative Diseases, Advances in Experimental Medicine and Biology, Vol. 664, 2010, pp. 631-638: *Section 12.3, pages 633-634, describes circuits underlying vision, proposing that a low-probability genetic event by which trichromatic color vision arose in primates produced an immediate advantage "by adapting some pre-existing visual circuit for a new purpose", possibly "the high-acuity spatial vision circuit" or "the pre-existing color vision circuit which compared S vs. L cones to provide blue-yellow color vision." *Section 12.4, pages 634-637, discusses in more detail circuits that might provide blue-yellow color vision, and Fig. 72.1 on page 635 compares circuits for dichromats and trichromats, both in a small bistratified ganglion pathway and a midget ganglion pathway. *Section 12.5, pages 637-638, discusses gene therapy to cure human red-green colorblindness, arguing as follows at page 637: "Because all of the circuitry required for taking advantage of a third cone type is already present in dichromatic individuals, it should be possible to transform an adult dichromat to a trichromat with full red-green color vision through the simple addition of the missing photopigment of the retina."